In 1609, the region was explored by Henry Hudson. A land purchase was made in this town in 1666 from local natives and confirmed as a patent in 1671. The region was known as Haverstroo, meaning "oat straw".

During the American Revolution, it served as an important lookout for British activities on the Hudson. A blue-marked trail, the Long Path, may be taken 2 miles (3 km) eastward from Central Highway along the crest of South Mountain to High Tor. Halfway is Little Tor, the second highest peak on South Mountain.

In 1826 the town was the site of a short-lived effort to establish a Owenite colony called the Franklin Community.[4] Underfinanced and wracked by internal dissent, the model Owenite community folded after a mere five months of operation.[4]

According to the United States Census Bureau, the town has a total area of 27.4 square miles (71.0 km2), of which 22.2 square miles (57.4 km2) is land and 5.3 square miles (13.6 km2), or 19.19%, is water.[5]

As of the census[6] of 2000, there were 33,811 people, 11,255 households, and 8,328 families residing in the town. The population density was 1,508.3 people per square mile (582.3/km²). There were 11,553 housing units at an average density of 515.4 per square mile (199.0/km²). The racial makeup of the town was 66.24% White, 10.27% Black or African American, 0.41% Native American, 3.21% Asian, 0.10% Pacific Islander, 15.65% from other races, and 4.12% from two or more races. Hispanic or Latino of any race were 31.73% of the population.

There were 11,255 households out of which 37.3% had children under the age of 18 living with them, 54.4% were married couples living together, 15.0% had a female householder with no husband present, and 26.0% were non-families. 21.3% of all households were made up of individuals and 7.8% had someone living alone who was 65 years of age or older. The average household size was 2.94 and the average family size was 3.43.

In the town the population was spread out with 26.3% under the age of 18, 8.6% from 18 to 24, 31.2% from 25 to 44, 23.6% from 45 to 64, and 10.3% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 93.7 males. For every 100 females age 18 and over, there were 89.4 males.

The median income for a household in the town was $53,850, and the median income for a family was $61,119. Males had a median income of $40,109 versus $31,979 for females. The per capita income for the town was $22,188. About 8.1% of families and 10.6% of the population were below the poverty line, including 12.8% of those under age 18 and 13.8% of those age 65 or over.

The town of Haverstraw is protected and served by over eighty men and women. The Village of Haverstraw Police Department merged with the Town of Haverstraw Police Department in January 2006 and now serve as one department protecting both the town and the village. HTPD serves under the command of Chief Charles B. Miller III. This police department is a diverse force and consists of about 80 police officers with one part-time police officer.

The Town of Haverstraw Police Department is home to five officers who received New York State's highest award for bravery in the line of duty. The New York State Police Officer of the Year award for 2000 was granted to Lieutenant Martin Lund, Sergeant Wayne Dunn, Sergeant John P. Lawless, Detective Brian Lauler and Police Officer Gregg Gaynor for their heroic acts. These officers repeatedly entered a burning three-story 52-unit apartment building to alert and evacuate many of the still sleeping residents. All of the officers had to brave thick smoke, intense heat and flames. They worked their way through the building, at times crawling on the floor, to escort frightened and disoriented residents from the building. Many small children had to be carried. Two of the officers suffered smoke inhalation and a third was treated for a laceration to his leg, as well as smoke inhalation. Governor Pataki recognized each officer for their actions in an award ceremony held in the village of Haverstraw.

Aaron Burr, third Vice President of the United States, was a frequent visitor to this area. It is said that Aaron Burr studied law at the office of Thomas Smith, owner of the Belmont House (Treason House), which was occupied by his brother, Joshua Hett Smith – the location where Major André, accompanied by Benedict Arnold who commanded West Point, had agreed to surrender West Point to the British for £20,000 ($1.1M in 2008 dollars). Legend says that Aaron Burr carved his initials in the mantel at the Treason House. The Haverstraw Post Office now stands were the office once stood.

General Marie Joseph Paul Yves Rock Gilbert du Motier, better known as the Marquis de Lafayette, was a Revolutionary War hero and a leader of the Garde Nationale during the French Revolution. His camp was located on a hill in the western area of Haverstraw and the site has since been known as Camp Hill.